1. Field of the Invention
The invention is based on a device for determining at least one parameter of a flowing medium and on a method for separating a liquid from a medium flowing in a line.
2. Description of the Prior Art
A device with a measurement conduit is already known (German Patent Disclosure DE 197 35 891 A1) in which a measurement element is accommodated that is bathed there by the inflowing medium. The medium flows from an inlet conduit first into a deflection conduit, which has a larger flow cross section than the inlet conduit and has a right-angled corner, so that there is an abrupt flow transition in the form of a step to the inlet conduit. Next, deflected by the corner of the deflection conduit, the medium flows along the peripheral face of the deflection conduit into an outlet conduit adjoining it transversely and leaves the outlet conduit through an outlet opening and then mixes again with the medium flowing past the device.
An inlet conduit longitudinal axis and an outlet conduit longitudinal axis are inclined by a predetermined angle from the longitudinal axis of the line, so that the inlet conduit has a region that is shaded from a main flow direction. The measurement element is disposed in the shaded region of the measurement conduit, to prevent soiling and resultant defects in the measurement element.
Water entering the intake line, for instance if the roadway is wet with rain, can sometimes cause contamination of the measurement element. Natural components of dissolved salts contained in this splashing water then cause a drift in the characteristic curve of the measurement element, because of the formation of a salt crust on the diaphragm of the sensor part. Although the inclination of the measurement body does form a partitioned-off region, nevertheless liquid particles reach the measurement conduit.
From German Patent Disclosure DE 197 41 031 A1, a measuring device with an inlet conduit is known in which a speeding up of the flow in the inlet conduit can be maintained by the design of two walls of the inlet conduit, but it is known that this leads only to stabilizing the flow of the medium in the inlet conduit, in particular in the measurement conduit.
The device and method according to the invention have the advantage over the prior that a measurement element is protected against liquid in a simple way.
It is advantageous to embody a liquid separation element in a conduit at least partly in labyrinthine fashion, because in this way liquid can be separated out yet liquid from the outside cannot penetrate into the conduit.
It is advantageous to embody the liquid separation element in an inner wall of a deflection conduit of the device, because this improves the separation.
Internested annular-arclike elements, which are simple to produce from a technical standpoint, are an advantageous embodiment of the liquid separation element.
It is advantageous to increase the flow resistance of the liquid separation element compared to the flow resistance of a measurement conduit, because as a result the great majority of the gaseous component of the flowing medium remains in the measurement conduit.
It is also advantageous to provide a deflection conduit in the inlet conduit that deflects the flow from the inner wall, because the deflection of the flow is facilitated thereby.
For good separation of liquid, it is advantageous that there is a detachment edge in the deflection conduit, which prevents deposited water from moving in the form of a wall film into the measurement conduit.
To stabilize the measurement signal, it is advantageous that the flow cross section of the inlet conduit and/or the outlet conduit narrows in the flow direction.